Piston expander



Failenteoi. Mov [3@5 U A assenso rrs'rorv naseizoen liter iill Eaton, Hagerstown, inet, assigner to 'Elie liter-liest Circle Gompanv, Hagerstown, limiti., a corporation ci indiana .iipplieation November 2, i942, Serial ofliifili s claims. leises-im v This invention relates to piston expanders and more particularly to piston espandere adapted to expand the skirt of a piston of aninternalcombustion engine 'and the like to proper diameter for efcient operation;

Heretofore, various Well-known types of one piece resilient piston espandere have been pro vided for expanding the slsirt of a piston to proper diameter in order to overcome the ecct of Wear or collapse of the piston skirt. l'iowever,l

'installation of these various one-piece types in operative expanding position within the piston has been found to be quite dimcult in that it has ,been necessary either to remove the piston pin,

or to collapse or distort the expander when insorting it Within the piston, or to slide the expaneler having the one-piece skirt bearing surface to operative position py the exertion of a considerable amount of pressure anol eort to overcome the relatively great trictional resistance between its relatively large bearing surface and. the piston skirt, all ci which was tedious and time consuming and required considerable skill and the use of special tools. Also it has been found that such expanden; which were so col lapseo'i and plied witlitools during installation may remain permanently distorted and sometimes failed to maintain themselves in operative position and to perform emcientiv during engine operation; while other one-piece expanders of the type which were, more easily inserted, because not constructed for a tight t or for a close engagement with the interior piston projections, became loose and disengaged from the piston during engine operation.

Oneof the objects ci my invention is to provide a highly emcient piston expander cl'n'npris-u ing a piston skirt-engaging surface comprising sections movable relatively to each other from open or non-expantling position to closed or op. erative piston-expanding position and which may7 be readily placeol within a piston in open posi= A to a minimum for relatively easy and effortless installation.,

A further object of my invention is to provide a piston skirt expander comprising two skirtengaging sections pivotailv and eccentrioally mounted with respect to each. other and relatively movable from open non-expanding position to closed expanding position by means of a toggle action with a minimum of eort.

A still further object oi my invention is `to provide an inexpensive, light, resilient piston expander which is capable of maintaining itself in operative pistomexpanding position within a piston Without loosening or becoming disengage therefrom during engine operation.

@ther and kfurther objects and advantages will become apparent as this description progresses, reference being had to the accompanying drawing, in which:

o Figure i is a vertical sectional view of an intornai combustion engine piston with a piston pin nountecl therein illustrating the improved piston skirt expander comprising my invention in lopn erative piston-expanding position therein between the piston pin and the piston skirt;

Fiel. 2 is a vertical sectional view of a piston and my improved piston skirt expander taken on the line 2--2 in Figure l looking in th'e direction of the arrows;

Fis. 3 is a horizontal sectional view taken on the line ii-il in Figure l looking in the direction oi the arrows upwardly into the interior of the piston:

Fig. i is a horizontal sectional view similar to Fig. 3 loutillustrating my improved piston skirt expander in open inoperative position upon initial insertion into the piston and before being moved to closed piston-expanding position;

Fige 5 is a vertical sectional, view tekenen the line 5 5 in Fig. Il looking in the direction of the arrows; and

Fig. 6 is a perspective view of the improved piston skirt expander comprising my invention locked in closed position.

The improve@ piston skirt expander comprising my invention has been illustrated in the drawing as applied to an internal combustion engine piston it of the usual type having a hear il at its upper end and cylindrical side walls comprising a plurality of annular piston ring grooves i2 adjacent the head and a solici skirt i3 extending downwardly from the ring grooves l2, Extending inwardly from the inner periplh ervjof the piston skirt i3 are opposed piston pin bosses It through which a piston pin is ex tends for operable connection to a connecting rod oi the usual type (not shown). Although a solid skirt piston I has been illustrated in the drawing it is to be understood that my improved piston skirt expander 'is equally well adapted for application, to other types of pistons including the split skirt type.

Speciilcally. as shown more particularly in Fig. 6 ofthe drawing, the piston skirt expander I6 comprising my invention comprises a generally channel-shaped and longitudinally extending shell formed of resilient metal which is adapted to be disposed longitudinally within the piston Il with its longitudinal axis in parallel relation to thel axis of the piston I0 and adapted to extend when in operative piston-expanding position between the piston pin I and the piston skirt I3. 'The outer ends or base portions Il and Il of the channel-shaped shell are each cut away as at la in a considerable arc forming thereby the outline of almost a complete semi-circle. The base portions I'I and I8 are adapted to engage the piston pin l5 adjacent the pin bosses I4, the pin i5 being received within the cutaway portions I9 and in' engagement with the portions I1 and IB at all points of the arc. This considerable arc of the cutaway portions I9 provides a denite and intimate engagement with the piston pin I5 and prevents inadvertent loosening of the pis-` ton expander I6 from operative piston-expanding position within the piston during engine operation. Although the base portions of the expander have been illustrated and described in engagement with the piston pin, it is to be understood that they may be constructed for engagement with the piston pin bosses or other :suitable interior projections.

'Ihe piston skirt-engaging portion of the'channel-shaped shell is split transversely to form two.

transverse channel-shaped skirt-engaging sections 20 and 2| .which are adapted to be in substantial longitudinal alignment when in operative skirt-engaging position as shown in Fig. 1 of the drawing. The skirt-engaging section 2U is formed integrally with the base portions' I1 and I8 while ther skirt-engaging section 2| is pivotally and eccentrically mounted on the base portions Il and Il by means of rivets 22 and 23. These skirt-engaging sections 20 and 2| are, therefore, movable relatively to each other from open inoperative position to closed piston-expanding position, 'the relative opening movement of these sections 20 and.2| being limited by outwardly directed stop flanges 24 and 25 carried by the base portions I1 2! and 2| is provided in its skirt-engaging surfaces with aligned and similarly shaped expansion formations or grooves 2S and 2l, respectively, extending longitudinally of said sections 20 and 2|,

and with additional aligned and similarly shaped expansion formations or bulges 28 and 2S, and 3l). vand 3|, respectively, which extend laterally beyond and overhang the base portions I and I8. These expansion formations 26 and 21, 2.8 and 29, and

'Stand 3| are adaptedto increase the inherent resiliency of the expander I6 for more emcient piston expansion. The skirt-engaging sections 20 and 2| are also provided with apertures 32 and 33 which are centrally disposed in the expansion grooves 2@ and 2l and serve to edectively locate the sections in the forming dies during manu- 5 facture. The aperture 33, however, has an additional function which will be described hereinafter.

In order to lock the skirt-engaging sections 20 and 2| together in operative expanding position 10 and prevent their opening during engine operation, there is provided a latching means comprising a locking nger 34 which extends longitudinally as an integral part of section 2li fromthe expansion groove 26 thereof in a plane oset slightly downwardly therefrom. The locking finger 34 ls provided adjacent its free end with a semi-circular hook or tongue 35 which may be punched upwardly out of the body portion of the linger 34 so as to slant in a direction toward the section 20. With the sections 2d and 2| in closed operative position 'the locking nger v34 underlies the expansion groove 2l of section 2| and itstongue 35 is received within the aperture'33 in the lower portion of the expansion .groove 21, thereby preventing inadvertent relative opening movement of the sections 20 and 2|. The section 2| is cutaway centrally at its inner edge as at'36 to eliminate interference of the section 2| with the locking nger 34 and permit full closing of the sections 20 and 2l.

The piston skirt expander above described in detail may be readily and quickly installed in operable position in a piston by an operator of minimum mechanical skill with a minimum of eiort 35 without the use of tools and without removal of the piston pin I5. The rst steps in making such installation are to set the expander I6 in fully open position with the stop flanges 24 and 25 in engagement with the tapered side edges 2 I of the section 2| and then place the opened expander IG in initial position in the piston ID with the base portions I'I and I8 in engagement with the piston pin I5 adjacent the pin bosses I4 and with the bearing surface of the pivoted transverse section 2| in complete engagement with the inner periphery of the piston skirt I3. In this initial stage of installation, the expander I6 assumes the position illustrated in Figs. 4 and 5 of the drawing with.

the pivoted transverse section 2| well up within the piston in engagement with the'skirt and with the transverse section 20 extending downwardly and out of engagement with the piston skirt I3.

In the next and final stepin the installation, the operator, using onlyhis iingers and without any tools, may press against the end edges of the transverse section 2D and move the same upwardly in the direction of the arrow, as shown in Fig. 5, until the upstanding hook 35 of the locking nger 34 snaps into the aperture 33 of the section 2| locking the sections 2d and 2| together against relative opening movement. When this occurs, the piston expander I6 is completely closed and has been moved upwardly into nnal operative pistonexpanding position illustrated in Figs. 1, 2 and 3. 55 In this final closed and 'operative position, the

transverse sections 20 and 2| are in abutting relation in substantial longitudinal alignment and both are in expanding engagement with the piston skirt i 3. During the above described nal step, as the y transverse bearing section 20 is being pushed upwardly'to fully closed and operative position, the base portions II andi also move upwardly as they turn about the piston pin I5 so that the pivot points22 and 23 move upwardly in an arcuate Y eration.

direction as shown by the broken lines in Fig.

to a point or plane alcove the center axis of the piston pin i Simultaneously, the upward movement of the pivot points 22 and 23 causes upward sliding movement in adirecton axial of the piston I0 of the pivoted transverse section E i.. as it bears against the piston skirt @Si until its iinal operative position against the upper portion of the inner periphery of the piston skirt it is attained,

as shown in Fig. l of the drawing. The above described movement of the parts to operative and locked position wherein a relatively great expansive pressure is exerted by the expander, is ac= complishedthrough a toggle action effected hv the exertion of 'a relatively low pressure by the operator.

From the foregoing it is apparent that my improved piston expander hasl many inherent advantages, particularly in the case ci installation and eiliciency in performance during engine op- No frictional resistance occurs during installation between the other transverse shirtbearing section til and the piston skirt it or loetween the locking ringer d@ and the under surface of section El vuntil immediately before the hcoir of the locking iinger 3ft snaps into locking position inthe aperture of section 2i, the frictlonal resistance not occurrring until the final instant of installation due to the turning movement of section 2t which has a relatively small longitudinal dimension as compared to section El Aand, to the odset construction ci the locking iinger 34. Thus, although'my improved expander possesses a composite shirt-hearing surface that is relatively great in extent and therefore capable of emciently performing its shirt-expanding function, it lacks the inherent dimculty of installation possessed by expanders heg a onepiece skirt-bearing. surface which, normally can only be moved to operable position bp the enertion of a. relatively great amount of pressure and necessarily with the use of tools.

Another adventze resulting from' the twopiece bearing surface o f the expander is that the toggle movement of the parts is considerably reduced as compared to the relatively great extent of movement that would be necessary in the toggie action of an expander having a one-piece bearing surface to effect its movement tc operative position. Also, by using one of the transverse pieces or bearing sections as the connecting piece between the base portions through which the' toggie movement may be accomplished, double thicknesses ci' metal are avoided and the weight of the expander is materially reduced, thereby avoiding waste oi basic materials and reducing production It. will be understood that my invention isnot limited to the details of construction described with reference to the drawing and that other forms may be used without departing from the spirit and scope of my. invention as dened in A posed and ln alignment with the other part when in piston expanding position, and one o1' said skirt-engaging sections ,being 'rigidly connected to said base portions and the other of said skirtengaging sections being pivotallv srideccentrically mounted with respect to said base portions.

2. A piston skirt expander in the form of a channel-shaped shell of resilient metal comprising two transversely extending sections adapted to engage the inner periphery of a piston skirt and being movable relatively to each other from open inoperative position to closed piston-expanding position, and base portions supporting said transverse sections and adapted to engage surfaces Within a piston, each section having a skirt engaging part, one part being superimposed and in alignment with the other part when incpiston expanding position, and one of said sections being rigidly connected to said base portions and the other ci said sections being pivctaliy and eccentric-,ally mounted on said base portions. 3. il. piston skirt expander in the form of a transversely split channel-shaped shell or resilient metal comprising two transversely extending sections adapted to engage the inner periphery of a piston skirt and being movable relatively to each other from open inoperative position to closed piston-expanding position, base portidns supporting said transverse sections and adapted to engage projection means within a' piston, each section having e; skirt engaging part, one part being superimposed and in alignment with the other part when in piston expanding position, and one of` said sections being pivotally and eccentrically mounted on said base portions and the other of said sections being rigidly connected to said base portions, and means for limiting relative opening movement of said transverse sections.

e. 1A piston skirt expander in vthe form of a channel-shaped shell of resilient metal comprising two relatively movable and transversely extending piston skirt-engaging sections and hase portions supporting said skirt-engaging sections and being cut away at their side edges in a substantially semi-circular arc for engagement with a piston pin', the radius of said arc being substantially the same as that of the pistony pin, each section having a skirt engaging part, one part being superimposed and in alignment with. the other part when in piston expanding position. and one of said skirt-engaging sections being rigidly connected to said hase portions and the other of said skirt-engaging sections being. pivctally and eccentrically mounted on said base Porti.

5. A piston skirt expander in the form of a channel-shaped shell of resilient metal comprising two transversely extending sections adapted to ege the inner periphery of a piston skirt and being movable relatively to each other from open inoperative position to closed piston-expanding position, base portions supporting said transverse sections and adapted to engage projection means within a piston, each section having a skirt engaging part, one part being superimposed and in alient with the other part when in piston expanding position, one o' said sections being 'rigidly connected to said base portions and the other of said sections being pivotally and eccentrlcally mounted on said base portions, and locking means for maintaining the transverse sections In closed operative position. comprising a longitudinal extension canled by one of said sections and adapted to underlie the other of said sections when in closed position and elements between sald extension and said other section adapted to be 'interlockingly engaged when said sections are in closed position. l 

